PROJECT SUMMARY The unifying goal of the Developmental Core of the Center for AIDS Prevention Studies (CAPS) is to support trainees and scientists in their efforts to conduct high-impact, innovative, and timely HIV prevention research with the highest ethical standards that aligns with the mission of CAPS. The landscape of the HIV epidemic is changing rapidly, and there is a critical need for multi-disciplinary research to optimize recent and forthcoming advances and to address new challenges in HIV prevention. Social and behavioral research is paramount to the development, evaluation, and implementation of cutting-edge approaches to preventing HIV and its consequences. In this innovative iteration of CAPS, the Developmental Core will coordinate a wide range of resources and services that will (1) stimulate innovative, timely, high-impact, multi-disciplinary research that addresses current and emerging issues in HIV prevention and treatment; (2) build the number, effectiveness, and diversity of investigators trained to conduct high-impact HIV research; and (3) nurture a scientific environment that fosters innovation, partnerships and interdisciplinary collaborations to address emerging issues in the HIV epidemic. Examples of new directions proposed in this application are a reinvigoration of our pilot grants program to include a Multi-Principal Investigator pilot grant mechanism to foster team science and trans-disciplinary collaborations, an award for outstanding service to our robust internal peer review program, and a new focus on increasing the effectiveness of mentors. Through careful coordination with the other CAPS cores, the Developmental Core seeks to optimize the innovation and impact of HIV prevention science while attracting, supporting, and retaining diverse new investigators dedicated to ending the HIV epidemic and associated health and social disparities.